Samuel Pierpont Langley
2 Allegheny Observatory
9.1 Notes 9.2 Bibliography
10 External links
He was born in
Langley's steam-powered Aërodrome No. 5 in flight, May 6, 1896. Photo by Alexander Graham Bell
Langley attempted to make a working piloted heavier-than-air aircraft.
His models flew, but his two attempts at piloted flight were not
successful. Langley began experimenting with rubber-band powered
models and gliders in 1887. (According to one book, he was not able to
reproduce Alphonse Pénaud's time aloft with rubber power but
persisted anyway.) He built a rotating arm (functioning like a wind
tunnel) and made larger flying models powered by miniature steam
engines. Langley realised that sustained powered flight was possible
when he found that a 1 lb. brass plate suspended from the
rotating arm by a spring, could be kept aloft by a spring tension of
less than 1 oz.
Langley understood that aircraft need thrust to overcome drag from
forward speed, observed higher aspect ratio flat plates had higher
lift and lower drag, and stated in 1902 “A plane of fixed size and
weight would need less propulsive power the faster it flew”, the
counter-intuitive effect of induced drag.
He met the writer
Through Roosevelt I met Professor Langley of the Smithsonian, an old man who had designed a model aeroplane driven—for petrol had not yet arrived—by a miniature flash-boiler engine, a marvel of delicate craftsmanship. It flew on trial over two hundred yards, and drowned itself in the waters of the Potomac, which was cause of great mirth and humour to the Press of his country. Langley took it coolly enough and said to me that, though he would never live till then, I should see the aeroplane established.
His first success came on May 6, 1896 when his Number 5 unpiloted model weighing 25 pounds (11 kg) made two flights of 2,300 ft (700 m) and 3,300 ft (1,000 m) after a catapult launch from a boat on the Potomac River. The distance was ten times longer than any previous experiment with a heavier-than-air flying machine, demonstrating that stability and sufficient lift could be achieved in such craft.
On November 11 that year his Number 6 model flew more than 5,000 feet
(1,500 m). In 1898, based on the success of his models, Langley
received a War Department grant of $50,000 and $20,000 from the
Smithsonian to develop a piloted airplane, which he called an
"Aerodrome" (coined from Greek words roughly translated as "air
runner"). Langley hired
Charles M. Manly
Langley, right, with test pilot Charles Manly
While the full-scale Aerodrome was being designed and built, the internal combustion engine was contracted out to manufacturer Stephen M. Balzer (1864–1940). When he failed to produce an engine to the power and weight specifications, Manly finished the design. This engine had far more power than did the engine for the Wright brothers' first airplane—50 hp compared to 12 hp. The engine, mostly the technical work of men other than Langley, was probably the project's main contribution to aviation. The piloted machine had wire-braced tandem wings (one behind the other). It had a Pénaud tail for pitch and yaw control but no roll control, depending instead on the dihedral angle of the wings, as did the models, for maintaining roughly level flight.
First failure of the manned Aerodrome, Potomac River, Oct. 7, 1903
In contrast to the Wright brothers' design of a controllable airplane that could fly against a strong wind and land on solid ground, Langley sought safety by practicing in calm air over the Potomac River. This required a catapult for launching. The craft had no landing gear, the plan being to descend into the water after demonstrating flight which if successful would entail a partial, if not total, rebuilding of the machine. Langley gave up the project after two crashes on take-off on October 7 and December 8, 1903. In the first attempt, Langley said the wing clipped part of the catapult, leading to a plunge into the river "like a handful of mortar," according to one reporter. On the second attempt the craft broke up as it left the catapult (Hallion, 2003; Nalty, 2003). Manly was recovered unhurt from the river both times. Newspapers made great sport of the failures, and some members of Congress strongly criticized the project.
Langley's 1⁄4-scale model; it flew several hundred yards on August 8, 1903.
The Aerodrome was modified and flown a few hundred feet by Glenn Curtiss in 1914, as part of his attempt to fight the Wright brothers' patent, and as an effort by the Smithsonian to rescue Langley's aeronautical reputation. Nevertheless, courts upheld the patent. However, the Curtiss flights emboldened the Smithsonian to display the Aerodrome in its museum as "the first man-carrying aeroplane in the history of the world capable of sustained free flight". Fred Howard, extensively documenting the controversy, wrote: "It was a lie pure and simple, but it bore the imprimatur of the venerable Smithsonian and over the years would find its way into magazines, history books, and encyclopedias, much to the annoyance of those familiar with the facts." (Howard, 1987). The Smithsonian's action triggered a decades-long feud with the surviving Wright brother, Orville. Langley had no effective way of addressing the Wright brothers' central innovation of controlling an airplane too big to be maneuvered by the weight of the pilot's body. So if the Aerodrome had flown stably, as the models did, Manly would have been in considerable danger when the machine descended, uncontrolled, for a landing—especially if it had wandered away from the river and over solid ground. Legacy Air and sea craft, facilities, a unit of solar radiation, and an award have been named in Langley's honor, including:
Langley Gold Medal
In 1880 Langley invented the bolometer, an instrument initially used
for measuring far infrared radiation. The bolometer has enabled
scientists to detect a change of temperature of less than 1/100,000 of
a degree Celsius. It laid the foundation for the measurements of the
amount of solar energy on the Earth. His published an 1881 paper on
^ "Tableaux des prix décernés". Comptes rendus hebdomadaires des
séances de l'Académie des sciences. 117. 1894. p. 1006.
(The French Academy awarded the 1893 prizes on 18 December 1893.)
^ "Science Prizes". American Naturalist. 28. U. of Chicago Press.
1894. p. 290.
^ BIOGRAPHICAL INDEX OF FORMER FELLOWS OF THE ROYAL SOCIETY OF
EDINBURGH 1783 – 2002 (PDF). The Royal Society of Edinburgh. July
2006. ISBN 0 902 198 84 X.
American Antiquarian Society
A Dream of Wings: Americans and the Airplane, 1875-1905, by Dr. Tom D. Crouch, W. W. Norton, 1981 Taking Flight: Inventing the Aerial Age, from Antiquity through the First World War, by Dr. Richard P. Hallion, Oxford University Press, 2003 Wilbur and Orville: A Biography of the Wright Brothers, by Fred Howard, Dover, 1987 A Heritage of Wings, An Illustrated History of Naval Aviation, by Richard C. Knott, Naval Institute Press, Annapolis, Maryland, 1997 Winged Shield, Winged Sword: 1907-1950: A History of the United States Air Force, by Bernard C. Nalty, University Press of the Pacific, 2003 Aviation, The Pioneer Years, edited by Ben Mackworth-Praed, Studio Editions, Ltd., London, 1990 To Conquer The Air—The Wright Brothers and the Great Race for Flight, by James Tobin, Free Press, division of Simon & Schuster, 2003 "Vita ed opere dell'astronomo e costruttore aeronautico Samuel Pierpont Langley", by Giuseppe Ciampaglia. Rivista Storica; Gennaio 1996. Selling the True Time: nineteenth-century timekeeping in America, by Ian R. Bartky, Stanford University Press, 2000
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